Rossiter - a Republic of Ireland under-16 international right back - signed professional terms in the summer of 2002 with the club in, what would become, the final months of the Peter Reid era.
However, it wasn’t until the appointment of the much-maligned Howard Wilkinson that the Irishman got his chance. Replacing summer signing Stephen Wright, he lined up in a back four consisting of Emerson Thome, Stan Varga and a young George McCartney in a League Cup third round comeback win at Highbury over Arsenal.
The lads went in at half time 2-0 down due to goals from Robert Pires and Francis Jeffers and it looked like an early cup exit was on the cards - only for Sunderland to experience fifteen remarkable minutes which turned the game on its head. A sole Kevin Kyle goal and Marcus Stewart double meant Rossiter’s debut was memorable for more than just himself, as struggling Sunderland marched on to round four to tackle the waiting Sheffield United.
An impressive 2-0 win over Spurs and a battling 0-0 draw to the following Saturday at Liverpool meant that Rossiter struggled to get into the starting eleven in the league, with Wilkinson’s team starting to show some sort of form. That didn’t last long though and by the time the round four tie at Bramall Lane came along, the academy product was given another crack at full back. Division One Sheffield United though sprung a suprise with a Wayne Allison inspired victory that meant they progressed at Sunderland's expense.
A focus on improving the league form meant the youngsters who had been thrust into the team in the cups were not risked, and Rossiter wasn't seen again until we played Bolton Wanderers in the FA Cup.
Named on the bench, an early injury to Stephen Wright meant that Rossiter would be thrown into the action barely fifteen minutes into the game. Sunderland conceding within a minute of his introduction was bad enough but things were about to become a lot worse.
On the pitch less than ten minutes, Rossiter suffered an injury to his right knee that would sideline him for the majority of the season. Although it would turn out to be his final appearance in a Sunderland shirt, the 19-year-old recovered suffiencienty to make his Republic of Ireland under-21 debut three months later - only to suffer another serious injury, this time in his left knee.
The full back had been complaining of a stiffness in his left knee during training sessions prior to his return from his opposite knee, but when the surgeons looked further into the pain he was suffering from, what they found was life changing.
I recovered from the first time when I injured the right knee and could play and train, but it was getting a bit stiff and sore.
When I was at Lilleshall getting treatment after doing my cruciate, I still got pain in the right knee and started to get a lot of swelling.
It was then that they looked into it and found the tumour and I was sent to the specialist.
A cancerous growth was found in the left knee. The full back waited for weeks anxiously as he awaited the outcome of tests.
Thankfully for the youngster, tests came back with positive news. The tumour was benign. Surgeons removed the tumour, whilst also operating on his troublesome right knee by removing part of his hip bone to graft into his knee. An experienced professional athlete going through this level of complications would struggle to continue to play - for a 19-year-old, it must have been devastating.
Rossiter knew that there was a chance he would not play again, despite being given a brand new one year contract by new Manager Mick McCarthy. In 2004 it appeared he would not as he retired from the game, returning to his native Ireland. It was here though where a chance at Irish Premier Division side Finn Harps helped him rehabilitate. Within a year former Port Vale player Sean Connor brought him fully out of retirement to sign for Bohemians.
Remarkably Bohemians won the double that year, winning the title by a clear 19 points and beating Derry City on penalties to lift the FAI Cup - whilst this also gave the Irish team a shot at the Champions League qualifiers.
Disapointingly they went out to Red Bull Salzburg, but he would again go on to win his second career title at Bohs later that year. Since then, the now 33-year-old has stayed in the Irish league, competing for the league title whilst at Dublin St. Patricks and Dundalk before moving onto Longford Town in 2015. Although he was released by them in the summer, the story of Mark Rossiter’s career is a positive one to look over when you look at the challenges faced, a real triumph against the odds, whilst his career is also a testament to the old Sunderland adage of keeping the faith.
He said of his career back in the summer of 2003: "I'm not one of life's worriers. I don't see much point in dwelling on things you can't change" - but it may be worth looking back if you ever need a feel good story of triumph against the odds.